26o ANGIOSPERMAE—DICOTYLEDONES 



back as to touch both anthers. According to Hildebrand's investigations autogamj' 

 is always effective. 



2249. S. officinalis L. (Sprengel, 'Entd. Geh.,' pp. 62-4; Hildebrand, 

 op. cit.; Delpino, 'Ult. oss.'; Herm. Miiller, 'Fertilisation,' pp. 480-1, ' Weit. Beob.' 

 Ill, pp. 55-6; Ogle, Pop. Sci. Rev., London, viii, 1869; Knuth, ' Bloemenbiol. 

 Bijdragen,' ' Grundriss d. Blutenbiol.,' pp. 83-4; Kirchner, 'Flora v. Stuttgart,' 

 pp. 618-19; Correns, op. cit.; Schulz, ' Beitrage,' II, pp. 195 and 1917.) — The 

 violet-coloured, protandrous flowers of this species are marked on the lower lip with 

 dark-violet and whitish streaks which serve as nectar-guides. A ring of hairs in the 

 corolla-tube immediately above the nectar acts as a nectar-cover. 



The flower mechanism differs from that of S. pratensis in the following 

 particulars. The upper lip is short, but so broad that it protects the mouth of the 

 flower from rain. The two connective-joints are much shorter than in S. pratensis. 

 The lower anther-lobes generally still contain some pollen, but they are always much 

 smaller than the upper ones, and contain only a quarter or, at the most, half as many 



pollen-grains as the latter ; they are seldom 

 completely vestigial. The lower limb of the 

 connective is therefore not modified into a 

 plate closing up the flower-entrance, but is 

 kidney-shaped, almost like the upper one, 

 only slightly smaller. The hammer 

 „.,?'?■ 3s°- SaMa officinalis, L.(^h^T^<ivm mechanism of this species may therefore 



MuUer). Flower after removal of the right halt ^ J 



of the calyx and corolla, seen from the right side. be Considered less Complete than that of 



a, filament ; 5 c, connective ; £f£, upper and lower _, • t> i. i i. r t_ i_ 



anther-lobes; g, stigma; h, nectary; i, ovary; »• pratCnSlS. BOth lODeS Ot the anttierS are 



k, vestigial anther ; /, nectar-cover. situated in the mouth of the flower, the 



upper projecting slightly more forward than the lower. They lie so close together 

 that both are always turned downwards simultaneously, and also resume their original 

 positions together. A bee visitor can easily reach between the diverging filaments to 

 the nectar. In doing so it must first strike against both lower anther-lobes with its 

 head and receive pollen on its back from the upper lobes, which are now depressed. 

 In young flowers the stigma with its still apposed branches projects but little from 

 the upper lip, but in older flowers it hangs down in the entrance of the flower in 

 such a position that a bee visitor must deposit pollen on the diverging stigmatic 

 branches. 



Schulz observed purely female stocks at Bozen. He also sometimes found the 

 flowers perforated by Bombus terrester L. 



Visitors.— Herm. Miiller (H. M.) Borgstette (B.) and Buddeberg (Budd.) 

 observed the following. — 



A. Diptera. Syrphidae: i. Melanostoma ambigua Fall., po-dvg. (H. M.). 

 B. Hymenoptera. Apidae -. 2. Anthidium manicatum L. 5, skg. (H. M.) ; 

 3. Anthophora aestivalis Pz. 5, do. (H. M.) ; 4. Bombus agrorum L. 5, do. (H. M., 

 Strasburg, B.) ; 5. B. hortorum L. j, do. (H. M., Thuringia) ; 6. B. pratorum L. 

 5 and 5, do. (H. M., Thuringia) ; 7. B. pomorum Pz. 5, skg. and po-cltg. (H. M., 

 Thuringia); 8. B. rajellus K. 5, do. (H. M., Thuringia) ; 9. B. sylvarum L. j, skg. 

 (H. M.) ; 10. Chelostoma campanularum K. 5, skg. and po-cltg. (H. M., Thuringia); 

 II. C. nigricorne Nyl. $, skg. (H. M., Thuringia, Budd.); 12. Eucera longicornis L; 

 y and S, do. (H. M., Thuringia, B.) ; 13. Halictus sexnotatus K. % po-cltg. (H. M.) . 



